Phaedo is one of the dialogues of Plato the greatest difficulty in understanding. One of the issues of greatest importance that it is addressed is the duality body / soul. The plan of the dialogue is a dramatic narrative of the death of Socrates, that it is about to be executed is happy. His disciples strange that happiness and to justify the reason for his joy Socrates states that only then can embrace the object of his desire, the truth, because only when the soul is finally turn the body we can get the fullness of knowledge. Socrates defines the concept of death as the separation of body and soul, and this state, which separated him get the fullness of wisdom, as the body to the soul in this life is a kind of prison on the path to search for knowledge, so death is desired by anyone who loves wisdom. The theme of duality body / soul permeates all the dialogue, Plato articulates the relationship between these addressing it in different ways. There are two strands that are articulated in Phaedo the need to establish the separation of body and soul: the onto-epistemological and ethical-anthropological. The ethical sense blame the body in the human tendency to passions (66bss), in contrast with the soul that leads to the practice of virtues (68-69) and the philosophical activity, the onto-espitemological part of the states that Plato, for one hand, between body and perception-sensitive (aísthesis), and the soul and the acquisition of knowledge (epistême), more detail, between body and soul with the sensitive and understandable forms. Plato said that despises the body rather than soul reflect the statement that he despises the sense-perception rather than acquisition of knowledge. Many commentators and several compendia have been inspired by Phaedo and the Republic to defend the contempt which Plato, according to them, expressed by sensation. Todavia, this argument is causing a major problem in the understanding of the whole Platonic work, as in Theaetetus ( 152d) Plato identifies the body, in its sense-perceptual function, with knowledge, giving it a stake in this very important search. The reading of the Platonic works must be seeing the whole of his work, he writes not philosophize, but dialogues seeking a special care in its interpretation. The radical dualistic sense, this contempt for the body and the feeling attributed to Plato, it can be seen reading the Phaedo is resolved in the dialogue, from the arguments of reminiscence and the Theory of Forms. This paper examines the solution of problems that Plato develops in the dialogue and the possible difficulties of interpretation that may be encountered, with a view to the conclusion that develops in the dialogue on the nature of knowledge of good and of dialectics, in condensed Theory of Forms.